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【Objective】 To establish a co-expression lncRNA-mRNA ceRNA network and explore the potential molecular mechanism of lncRNA in dengue fever. 【Methods】 DENV-2-infected and normal pHUVEC were sequenced and screened for differentially expressed lncRNA and mRNA by gene microarray technology. Differentially expressed mRNA was analyzed by protein-protein interaction (PPI), and significantly related co-expressed lncRNA-mRNA was screened by Pearson’s correlation coefficient. The microRNA (miRNA) that bound to co-expressed lncRNA-mRNA was predicted by the database. The ceRNA network of co-expressed lncRNA-mRNA was constructed by Cytoscape software. Finally differentially expressed mRNAs and co-expressed lncRNA-mRNA were analyzed by GO and KEGG enrichment, and co-expressed lncRNA-mRNA was verified by RT-qPCR. 【Results】 At 48 h and 72 h after infection, 105 and 51 differentially expressed mRNAs were obtained, respectively, while 59 and 29 differentially expressed lncRNAs were obtained, respectively. Furthermore, at the two time intervals, there were 10 differential mRNAs and 5 differential lncRNAs, respectively. PPI analysis of differential mRNAs showed that isocratic values of interleukin 6 (IL6), interferon-induced protein with tetratricopeptide repeats 2 (IFIT2), and 2’-5’-oligoadenylate synthetase 2 (OAS2) were relatively high. The pairing results of lncRNA-mRNA co-expression analysis with the highest correlation coefficients at 48 h and 72 h after infection were XLOC_001966-SMTNL1 and XLOC_001966-ESR2, respectively. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the functions of differentially expressed mRNA and co-expressed lncRNA-mRNA were mainly involved in virus epidemic prevention response, immune response, and signal transduction, as well as the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway, type I interferon, and cytokine receptor interaction. RT-qPCR revealed that lncRNA XLOC-I2-8991 was upregulated in the co-expressed lncRNA-mRNA, whereas all the other lncRNA and mRNA were downregulated. 【Conclusion】 This study initially revealed the potential lncRNA-mRNA co-expression network during dengue virus infection, and found that co-expressed lncRNA-mRNA was mainly enriched in the immune regulation and signal transduction pathways during virus infection. The findings will help further exploration into the infection mechanism of DENV-2.
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OBJECTIVE@#To analyze the differentially phosphorylated proteins in DENV-2-infected human umbilical venous endothelial cells (HUVECs) and explore the possible pathogenic mechanism of DENV-2 infection.@*METHODS@#The total proteins were extracted from DENV-2-infected HUVECs and blank control HUVEC using SDT lysis method. The phosphorylated proteins were qualitatively and quantitatively analyzed using tandem mass spectrometry (TMT). The identified differentially phosphorylated proteins were analyzed by bioinformatics analyses such as subcellular localization analysis, GO enrichment analysis, KEGG pathway analysis and protein-protein interaction (PPI) analysis. Western blotting was used to detect the expressions of phosphorylated Jun, map2k2 and AKT1 proteins in DENV-2-infected HUVECs.@*RESULTS@#A total of 2918 modified peptides on 1385 different proteins were detected, and among them 1346 were significantly upregulated (FC > 1.2, P < 0.05) and 1572 were significantly downregulated (FC < 0.83, P < 0.05). A total of 49 phosphorylated conserved motifs were obtained by amino acid conservative motif analysis. The most abundant differentially phosphorylated peptides in protein domain analysis included RNA recognition motif, protein kinase domain and PH domain. Subcellular localization analysis showed that the differentially modified peptides were mainly localized in the nucleus and cytoplasm. GO enrichment and KEGG pathway analysis showed that the differential peptides were mainly enriched in the regulation of stimulation response, biosynthesis of small molecules containing nuclear bases, and migration of phagosomes and leukocytes across the endothelium. PPI and KEGG joint analysis showed that the up-regulated and down-regulated differentially phosphorylated proteins were enriched in 15 pathways. In DENV-2-infected HUVECs, Western blotting detected differential expressions of phosphorylated proteins related with the autophagy pathway, namely JUN, MAP2K2 and AKT1, and among them p-JUN was significantly down-regulated and p-AKT1 and p-MAP2K2 were significantly upregulated (P < 0.01).@*CONCLUSION@#DENV-2 infected HUVECs show numerous differentially expressed proteins. The downregulation of p-JUN and upregulation of p-MAP2K2 and p-AKT1 suggest their potential roles in regulating autophagy, which is probably involved in the mechanism of DENV-2 infection.
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Humans , Autophagy , Cell Death , Cell Nucleus , Human Umbilical Vein Endothelial Cells/virology , Dengue , ProteomeABSTRACT
@#The NS2B/NS3 protease is crucial for the pathogenesis of the DENV. Therefore, the inhibition of this protease is considered to be the key strategy for the development of new antiviral drugs. In the present study, malabaricones C (3) and E (4), acylphenols from the fruits of Myristica cinnamomea King, have been respectively identified as moderate (27.33 ± 5.45 μM) and potent (7.55 ± 1.64 μM) DENV-2 NS2B/NS3 protease inhibitors, thus making this the first report on the DENV-2 NS2B/NS3 protease inhibitory activity of acylphenols. Based on the molecular docking studies, compounds 3 and 4 both have π-π interactions with Tyr161. While compound 3 has hydrogen bonding interactions with Gly151, Gly153 and Tyr161, compound 4 however, forms hydrogen bonds with Ser135, Asp129, Phe130 and Ile86 instead. The results from the present study suggests that malabaricones C (3) and E (4) could be employed as lead compounds for the development of new dengue antivirals from natural origin.
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Abstract INTRODUCTION: In this study, we aimed to identify DENV-2 subtypes in Aedes aegypti pools collected between 2011 and 2017 in a rural area of Northern Cordoba, Colombia ("La Balsa"). METHODS: RT-PCR was performed to analyze the capsid/pre-membrane region (C-PrM). Sequencing and phylogenetic bayesian inference using reference DENV-2 sequences were performed. RESULTS: Twelve pools that tested positive for DENV-2 were characterized based on the C-PrM region and grouped under the Asian/American clade. CONCLUSIONS: This study is the first to report the DENV-2 Asian-American subtype in a rural area of Cordoba region, which is associated with severe dengue and local epidemics.
Subject(s)
Animals , Phylogeny , Aedes/virology , Dengue/virology , Dengue Virus/classification , Dengue Virus/genetics , Mosquito Vectors/virology , Serotyping , Bayes Theorem , Colombia/epidemiology , Severe Dengue , Reverse Transcriptase Polymerase Chain Reaction , Dengue/epidemiology , Dengue Virus/isolation & purification , SerogroupABSTRACT
Objective To study the influences on the production of major inflammatory cytokines after co-culturing macrophages with human umbilical vein endothelial cells ( HUVECs) that were infected with dengue virus type 2 (DENV-2). Methods Density gradient centrifugation was used to isolate periph-eral blood mononuclear cells ( PBMC) from concentrated human leukocytes. Adherent monocytes in culture flasks were obtained and stimulated with macrophage colony-stimulating factor ( M-CSF) to prepare macro-phages. The purity of CD14+CD11b+ cells was measured by flow cytometry. Changes in the expression of NS1 at mRNA level in HUVECs were detected by real-time PCR following DENV-2 infection. DENV-2-in-fected HUVECs were co-culture with macrophages in Transwell chambers. A control group was set up by pre-treating HUVECs with sphingosine-1-phosphate (S1P) type 1 (S1P1)-specific receptor agonist CYM-5442 for 24 h to remove the drug before infection and then co-culturing the infected cells with macrophages. Real-time PCR was used to detect the expression at mRNA level of IL-6 and IL-8 in HUVECs and IL-6, IL-8, TNF-α and IL-1β in macrophages. A double-antibody sandwich ELISA was used to detect the expression of above cytokines in culture supernatants. Results After HUVECs were infected with DENV-2, expression of NS1 gene at mRNA level gradually increased to the peak at 24 h (2. 66±0. 53, P<0. 05) and then de-creased. The purity of macrophages detected by flow cytometry was (89. 16±2. 07) ％. Expression of IL-6 and IL-8 at mRNA level in DENV-2-infected HUVECs was up-regulated. The peak values reached at 24 h of IL-6 and IL-8 expression were 16. 10±0. 17 and 29. 76±0. 58, while the expression levels at 24 h in the un-infected group were 1. 46±0. 67 and 1. 60±0. 54, respectively. Expression of IL-6, IL-8, TNF-αand IL-1βat mRNA level in DENV-2-infected macrophages was increased significantly. The levels of IL-6, IL-8, TNF-αand IL-1β expression at 24 h were 45. 82±3. 72, 52. 34±1. 69 (12 h), 8. 94±1. 75 and 30. 96±1. 44 in the infected macrophages, and 1. 16±0. 22, 1. 15±0. 21, 1. 11±0. 09 and 1. 47±0. 31 in the uninfected group. Expression of these cytokines was decreased at every time points after co-culturing of DENV-2-infec-ted HUVECs with macrophages, but still significantly higher than that in the uninfected group. In the co-cul-ture group with DENV-2 infection, CYM-5442 pretreatment significantly decreased the expression at mRNA level of IL-6 and IL-8 in HUVECs (P<0. 01) and that of IL-6, IL-8, TNF-αand IL-1βin macrophages (P<0. 01). Conclusions DENV-2 could infect primary HUVECs, and then activate macrophages to promote the secretion of large amounts of IL-6, IL-8, TNF-αand IL-1β. Moreover, the activated macrophages could reduce the production of inflammatory cytokines in HUVECs to a certain extent.
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Aim To screen novel NS5 inhibitors a-gainst dengue virus ( DENV) replication. Methods His-tagged DENV2 NS5 RNA-dependent polymerase ( NS5 RdRp ) was expressed and purified in BL21 cells. The binding ability of the small molecules to NS5 polymerase was determined by SPR assay. The activity of dengue inhibition by Z1 was determined by CPE, LDH and plaque assay. RNA synthesis was as-sessed by Real-time PCR. The dsRNA synthesis and viral proteins were detected by immunofluorescence as-say. The level of viral proteins was examined by West-ern blot. The stage of DENV life cycle was evaluated by time of drug-addition assay. Results A small mo-lecular Z1 was discovered, which could bind to NS5 RdRp. Z1 inhibited DENV2 RNA replication, synthe-sis of dsRNA and protein synthesis in post-entry stage of dengue life-cycle. Cell based assay confirmed that Z1 inhibited DENV-induced cell death with EC50 val-ues of 4. 75μmol·L-1 . Conclusions The novel NS5 inhibitor Z1, inhibits DENV2 RNA replication, protein synthesis and release of progeny virus, which may be severed as an anti-DENV2 antiviral drug for further de-velopment.
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Objective To investigate the influences on major inflammatory cytokines after co-cul-turing regulatory T cells (Treg) with human umbilical vein endothelial cells ( HUVECs) that were infected with dengue virus type 2 (DENV-2). Methods Peripheral blood mononuclear cells (PBMC) were extrac-ted from concentrated human leukocytes by density gradient centrifugation. Treg cells were sorted by immu-nomagnetic beads. Expression of CD4,CD25 and CD127 molecules on the membrane of Treg cells was detec-ted by flow cytometry to identify the purity of Treg cells. HUVECs pretreated with or without sphingosine-1-phosphate S1P type 1 (S1P1)-specific receptor agonist CYM-5442 for 24 h were first infected with DENV-2 and then co-cultured with Treg cells. Expression of IL-6,IL-8,TNF-α,IL-10 and TGF-β at mRNA level was detected by real-time RT-PCR. Levels of IL-6,IL-8,IL-10 and TGF-β in the culture supernatants were detec-ted by a double-antibody sandwich ELISA. Results The purity of Treg cells was (84. 3±0. 5)%. Expression of NS1 at mRNA level in DENV-2-infected HUVECs first gradually increased and then decreased after reac-hing the peak at 24 h (3. 03±0. 26, P<0. 01). Enhanced expression of IL-6,IL-8 and TNF-α at mRNA level in HUVECs was observed after DENV-2 infection ( P<0. 01). Expression of these cytokines at every time point was decreased after co-culturing DENV-2-infected HUVECs with Treg cells ( P<0. 05),but was still higher than that before infection. CYM-5442 pretreatment decreased the expression of IL-6,IL-8 and TNF-α at mRNA level in DENV-2-infected HUVECs and inhibited the secretion of IL-10 and TGF-β by Treg cells that were co-cultured with DENV-2-infected HUVECs. Conclusion Primary HUVECs infected by DENV-2 can enhance the secretion of IL-10 and TGF-β by Treg cells,and the suppressive cytokines produced by Treg cells can reduce the production of inflammatory cytokines by DENV-2-infected HUVECs.
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Objectives: To express and characterize NS1 of Indonesian-specific DENV2 virus in Pichia pastoris (P. pastoris). Methods: A codon optimized synthetic gene derived from the DENV-2 NS1 amino acid sequences was synthesized commercially and inserted into the P. pastoris pPICZαA expression vector. The recombinant DENV-2 NS1 protein was purified by Ni-NTA af-finity chromatography, and its antigenicity was tested. Results: The recombinant DENV-2 NS1 protein was secreted as a protein with a mo-lecular weight of ～45 kDa, and the optimal expression condition was achieved by in-duction with 2％(v/v) methanol for 72 h. The purified recombinant DENV-2 NS1 protein was able to interact with a monoclonal antibody of NS1 in a commercial rapid test. Conclusions: The resulting recombinant DENV-2 NS1 protein produced in P. pastoris KM71 is a potential candidate for use in the development of a dengue diagnostic kit and vaccine.
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Objective To investigate the effects of interaction between human umbilical vein endothelial cells (HUVECs) which were infected with dengue virus type 2 (DENV-2) and CD4+T cells on the expression of ICAM-1 (intercellular adhesion molecule 1),VCAM-1 (vascular cell adhesion molecule 1),IL-10 and TGF-β1 at mRNA level for further understanding the immunological mechanism of DENV infection.Methods HUVECs were treated with CYM-5442,a selective agonist for sphingosine-1-phosphate receptor 1 (S1P1),for 24 hours and then infected with 103 TCID50 (50% tissue culture infective dose) of DENV-2 before co-culturing with CD4+T cells.Changes in the expression of NS1 (DENV-2 nonstructural protein),SPHK1 (sphingosine kinase 1,phosphorylating sphingosine to S1P),ICAM-1,VCAM-1,IL-10 and TGF-β1 at mRNA level were detected by real-time PCR after 4,8,12,24,48 and 72 hours of co-culturing.Results There was a certain timeliness in the expression of NS1 at mRNA level after infecting HUVECs with DENV-2 and the expression reached a peak at 24 h.Treating HUVECs with or without CYM-5442 had no significant influence on the expression of DENV-2 NS1 at mRNA level.The expression of SPHK1 at mRNA level was significantly increased after treating HUVECs with CYM-5442 and DENV-2 (P<0.05).Compared with DENV-2-infected or untreated HUVECs,Co-culturing DENV-2-infected HUVECs with CD4+T cells increased the expression of ICAM-1 and VCAM-1 in HUVECs at mRNA level (P<0.01) as well as the expression of IL-10 in CD4+T cells at mRNA level (P<0.05),but had no significant influence on the expression of TGF-β1 in CD4+T cells at mRNA level.Conclusion This study shows that DENV-2 can replicate and proliferate in HUVECs,but CD4+T cells inhibit the replication and proliferation.CD4+T cells play an important role in promoting the expression of VCAM-1 and ICAM-1 in DENV-2-infected HUVECs at mRNA level,activating HUVECs and increasing inflammation,which may be associated with increased vascular permeability induced by DENV-2 infection.Co-culturing CD4+T cells with DENV-2-infected HUVECs promotes the expression of IL-10 in CD4+T cells at mRNA level,but has no significant effect on TGF-β1.
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Objective:To study the interaction of the inflammatory cytokines expression between CD4+ T cells and primary human umbilical vein endothelial cells (HUVECs) infected by dengue virus (DENV-2).Methods:PBMC was extracted from white blood cells by density gradient centrifugation,CD4+ T cells were sorted by immunomagnetic beads.The expression of CD3 and CD4 molecules on the surface of cells was detected by flow cytometry to identify the purity of CD4+ T cells.First,HUVECs were pretreated by specific-S1 P1 receptor agonist CYM-5442 for 24 h,second,infected by DENV-2 on the titer of 103 TCID50,then co-culturing with CD4+ T cells,The relative expression of NS1 partial sequence and IL-6,L-8 mRNA of HUVECs,and IL-4,IL-17,TNF-α,IFN-γ of CD4+ T cells detected by Real-time RT-PCR.IL-6 and IL-8 secreted in cultured supematant analyzed by ELISA.Results:The purity of CD4+ T cells was (98.02±0.32) ％.The expression of NS1 gradually increased to 24 h (3.03±0.26,P＜0.001),decreased after reaching the peak.The relative expression of NS1 in the group of co-cultured with CD4+ T cells was lower than other groups.After infection,the expression of IL-6 and IL-8 were up-regulated,and the expression of IL-6 and IL-8 at each time point was significantly increased after co-culturing with CD4+ T (P＜0.01).IL-6 of CYM-5442 pretreatment group,in 24 h (28.91±2.34,P＜0.05),36 h(19.36±0.1,P＜ 0.05) and 72 h(13.84±0.82,P＜0.05) was significantly decreased,the expression of IL-8 also decreased significantly.The mRNA expression of IL-4,IL-17,TNF-α and IFN-γ in CD4+ T cells was significantly increased after co-culturing with HUVECs.After the treatment with CYM-5442 group,the expression was decreased.Conclusion:DENV-2 could infect the primary HUVECs,and the expression of NS1 was inhibited after co-culturing with CD4+ T cells.CD4+ T cells can not only enhance the activation of HUVECs infected by DENV-2,but also can be activated by the infected HUVECs infected with DENV-2.
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Objectives To express and characterize NS1 of Indonesian-specific DENV2 virus in Pichia pastoris (P. pastoris). Methods A codon optimized synthetic gene derived from the DENV-2 NS1 amino acid sequences was synthesized commercially and inserted into the P. pastoris pPICZαA expression vector. The recombinant DENV-2 NS1 protein was purified by Ni-NTA affinity chromatography, and its antigenicity was tested. Results The recombinant DENV-2 NS1 protein was secreted as a protein with a molecular weight of ∼45 kDa, and the optimal expression condition was achieved by induction with 2% (v/v) methanol for 72 h. The purified recombinant DENV-2 NS1 protein was able to interact with a monoclonal antibody of NS1 in a commercial rapid test. Conclusions The resulting recombinant DENV-2 NS1 protein produced in P. pastoris KM71 is a potential candidate for use in the development of a dengue diagnostic kit and vaccine.
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Background & objectives: Dengue fever (DF) is associated with significant morbidity and mortality in the tropical and sub-tropical regions of the world. Since there are no effective antiviral drugs for treatment, clinicians often rely on the accurate diagnosis of dengue fever to begin supportive therapy at early stages of the illness. The objective of this study was to develop an in-house dengue virus serotype 2 (DENV-2) non-structural protein- 5 (NS5) based indirect ELISA. Methods: DENV-2 was raised in Vero cells and the viral proteins were separated and subsequently the NS5 protein was eluted. Serum samples from primary and secondary dengue fever patients; and acute and convalescent samples from Japanese encephalitis (JE) and West Nile virus (WNV) cases were used to validate the ELISA. Results: The assay was found to be 100 per cent specific in detecting DENV-2 specific antibodies from patient’s serum. However, in terms of sensitivity, the assay could detect IgM antibodies only from 90 per cent of the primary dengue samples. The IgM/IgG ratio of the primary and secondary samples was 7.24 and 0.64, respectively. Interpretation & conclusions: The results indicate that the DENV-2 NS5 ELISA is dengue group specific and can be used to differentiate dengue infection from other circulating Flavivirus infections. This NS5 ELISA can also be used to distinguish between primary and secondary dengue fever on the basis of IgM/IgG ratios. Further studies with larger sample sizes and different DENV serotypes are required to validate the ELISA.
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OBJECTIVE@#To describe the clinical manifestation of patient with severe dengue, to identify the serotypes and genotypes of dengue viruses (DENV) which concurrently infecting the patient, and to explore the possible relationship of severe dengue with the concurrent infection of DENV.@*METHODS@#Dengue diagnosis was performed using NS1 antigen detection and IgG/IgM ELISA. Standard clinical and laboratory examinations were performed to obtain the clinical and hematological data. DENV concurrent infections were detected and confirmed using RT-PCR and DENV Envelope gene sequencing. Phylogenetic analyses were performed to determine the genotypes of the viruses.@*RESULTS@#The patient was classified as having severe dengue characterized by severe plasma leakage, hemorrhage, and organ damage involving lung, liver, and kidney. Concurrent infection of DENV serotype 2 and 3 was observed. The infecting DENV-2 virus was grouped into Cosmopolitan genotype while DENV-3 virus was classified into Genotype I. Both viruses were closely related to isolates that were endemic in Jakarta. Viremia measurement was conducted and revealed a significantly higher virus titer of DENV-3 compared to DENV-2.@*CONCLUSIONS@#The occurrence of multi-serotype DENV infections was presented in a patient with severe clinical manifestation in Indonesia. The hyperendemicity of dengue in Indonesia may contribute to the DENV concurrent infections cases and may underlie the severity of the disease.
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Objective: To describe the clinical manifestation of patient with severe dengue, to identify the serotypes and genotypes of dengue viruses (DENV) which concurrently infecting the patient, and to explore the possible relationship of severe dengue with the concurrent infection of DENV. Methods: Dengue diagnosis was performed using NS1 antigen detection and IgG/IgM ELISA. Standard clinical and laboratory examinations were performed to obtain the clinical and hematological data. DENV concurrent infections were detected and confirmed using RT-PCR and DENV Envelope gene sequencing. Phylogenetic analyses were performed to determine the genotypes of the viruses. Results: The patient was classified as having severe dengue characterized by severe plasma leakage, hemorrhage, and organ damage involving lung, liver, and kidney. Concurrent infection of DENV serotype 2 and 3 was observed. The infecting DENV-2 virus was grouped into Cosmopolitan genotype while DENV-3 virus was classified into Genotype I. Both viruses were closely related to isolates that were endemic in Jakarta. Viremia measurement was conducted and revealed a significantly higher virus titer of DENV-3 compared to DENV-2. Conclusions: The occurrence of multi-serotype DENV infections was presented in a patient with severe clinical manifestation in Indonesia. The hyperendemicity of dengue in Indonesia may contribute to the DENV concurrent infections cases and may underlie the severity of the disease.
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Background & objectives: Dengue is a major health problem in many parts of India and its neighbouring countries. Dengue cases have not been reported from Manipur, a northeastern State of India till 2007. But, the sudden outbreak of fever with febrile illness during 2007 and 2008, suspected to be dengue/dengue haemorrhagic fever was investigated to detect the causative agent. Potential impact of climatic variables on dengue transmission has been documented and hence the association between climatic factors, entomological parameters and dengue cases was also analysed. Methods: Forty two and 16 blood samples were collected from patients suspected to have dengue infection in the year 2007 and 2008, respectively. Viral RNA was extracted from serum samples and subjected to multiplex one step RT-PCR assay. Dengue specific amplicons were sequenced and phylogenetic analysis was carried out. Multiyear trend analysis and ‘t’ test were performed for the comparison of different meteorological variables between the years 2000-2004 and 2005-2008. Results: The aetiological agent was found to be DENV-2 and the phylogenetic analysis showed that the isolate was similar to that of Cambodian isolate. There was a significant difference in minimum temperature (P<0.05), Relative humidity - morning hours (P<0.001), relative humanity - afternoon hours (P<0.01) and cumulative precipitation (P< 0.05) between the years 2000-2004 and 2005-2008. Interpretation & conclusions: The sudden outbreak of dengue fever in Manipur State occurred was possibly due to the increased temperature, relative humidity and decrease in cumulative precipitation. These climatic factors would have contributed to the Aedes mosquito abundance and increased virus transmission. Proper diseases surveillance system integrated with meteorological warning system and management of vector breeding sites will prevent such outbreaks in future.